MIPS questions lack of standards for testing rotational motion in helmets

ktache wrote:

They are stoatally different.

Thanks - I never realised how weaselly identifiable they are.

ktache wrote:

pop

That painting looks more like a stoat to me.

However, I can never tell the difference...

HawkinsPeter wrote:

ktache wrote:

pop

That painting looks more like a stoat to me.

However, I can never tell the difference...

How about one of these:

https://www.facebook.com/handpaintedstuff/posts/have-you-got-a-stoat-and-weasel-recognition-kit-yet-do-you-know-the-difference-i/2054452084788249/

Rich_cb wrote:

Please don't listen to Burt. Whole population studies are very unreliable as there are so many other variables that cannot be excluded. This is especially true if there are big changes in the population you are studying. Mandatory helmet laws produce such changes thereby making whole population data worthless.

Wut?  Surely the whole point of legislation is to have an effect on the whole population.

New Zealand has a compulsory helmet law with nearly 100% compliance.  Their bicycle use and accident and fatality rate is almost exactly the same as the UK which doesn't have a compulsory helmet law.  

Interestingly, I was watching an Australian paramedic show the other night when they attended a motorbike crash.  The paramedic made the comment that with the way motorbike helmets were constructed you'd think they'd save the head inside it and they don't.

jestriding wrote:

Wut?  Surely the whole point of legislation is to have an effect on the whole population.

New Zealand has a compulsory helmet law with nearly 100% compliance.  Their bicycle use and accident and fatality rate is almost exactly the same as the UK which doesn't have a compulsory helmet law.  

Interestingly, I was watching an Australian paramedic show the other night when they attended a motorbike crash.  The paramedic made the comment that with the way motorbike helmets were constructed you'd think they'd save the head inside it and they don't.

The effect the legislation has is different on different groups.

Imagine there were only 2 types of cyclists.

1. Road cyclist, always wears a helmet.
Mandatory helmet law has zero effect.

2. Occasional utility cyclist, doesn't wear a helmet as it messes up his hair.
Mandatory helmet law stops his cycling completely.

The cycling population pre law is 50% road, 50% utility. Post law it's 100% road.

This creates the bizarre situation where road cycling could actually get safer yet the national statistics could get worse. (If road cycling were a higher risk activity than utility cycling.)

When studying the effect of anything it's vital to keep other variables to a minimum.

Whole population studies can't do this hence why they are considered very weak evidence.

Rich_cb wrote:

jestriding wrote:

Wut?  Surely the whole point of legislation is to have an effect on the whole population.

New Zealand has a compulsory helmet law with nearly 100% compliance.  Their bicycle use and accident and fatality rate is almost exactly the same as the UK which doesn't have a compulsory helmet law.  

Interestingly, I was watching an Australian paramedic show the other night when they attended a motorbike crash.  The paramedic made the comment that with the way motorbike helmets were constructed you'd think they'd save the head inside it and they don't.

The effect the legislation has is different on different groups. Imagine there were only 2 types of cyclists. 1. Road cyclist, always wears a helmet. Mandatory helmet law has zero effect. 2. Occasional utility cyclist, doesn't wear a helmet as it messes up his hair. Mandatory helmet law stops his cycling completely. The cycling population pre law is 50% road, 50% utility. Post law it's 100% road. This creates the bizarre situation where road cycling could actually get safer yet the national statistics could get worse. (If road cycling were a higher risk activity than utility cycling.) When studying the effect of anything it's vital to keep other variables to a minimum. Whole population studies can't do this hence why they are considered very weak evidence.

So you're saying that even though there is no evidence of a population level reduction in head injuries, the unintended consequences of implementing a compulsory all age helmet law by reducing utility cycling (the evidence in New Zealand and Australia is that children biking to school has almost completely stopped), is evidence that population level studies are unreliable?

jestriding wrote:

So you're saying that even though there is no evidence of a population level reduction in head injuries, the unintended consequences of implementing a compulsory all age helmet law by reducing utility cycling (the evidence in New Zealand and Australia is that children biking to school has almost completely stopped), is evidence that population level studies are unreliable?

No. I'm saying that population level studies are unreliable because you cannot control for the huge number of variables at play.

Going back to the hypothetical scenario I described earlier.

Imagine that pre law the road cyclists had 50 head injuries per 1m miles and the utility cyclists had 0.

If both groups did the same number of miles the overall rate of head injury for the whole population would be 25 per million miles cycled.

After the law there are no utility cyclists and the injury rate for the road cyclists has fallen slightly to 49 per million miles cycled.

Nationally the number of head injuries per million miles will have increased hugely (to 49 from 25) and even the number of head injuries in total won't have changed much.

The numbers will look worse but cycling will be safer for those who still cycle.

That's why you cannot rely on population level data, even with just one variable you can produce completely misleading results.

jestriding wrote:

Interestingly, I was watching an Australian paramedic show the other night when they attended a motorbike crash.  The paramedic made the comment that with the way motorbike helmets were constructed you'd think they'd save the head inside it and they don't.

Despite their heavy, multi-layered construction, motorcycle helmets are only good up to about 16mph for direct blows, and of course they increase the risk of the most dangerous injury, rotational, and the weight makes neck injuries much more likely too.  The evidence that motorcycle helmets improve safety is very much the same as for cycle helmets i.e. lacking.

Rich_cb wrote:

Please don't listen to Burt. Whole population studies are very unreliable as there are so many other variables that cannot be excluded. This is especially true if there are big changes in the population you are studying. Mandatory helmet laws produce such changes thereby making whole population data worthless.

You really must explain your opinion of whole population, long term research to epidemiologists and statisticians, who seem to be of a rather different opinion, supported by the international standards for the reliability of research; but I'm sure you're right.   

Perhaps you could tell us what type of helmet research is more reliable?  According to those international standards that is, not your opinion.  Please don't say case control studies; my sides hurt enough already. 

burtthebike wrote:

You really must explain your opinion of whole population, long term research to epidemiologists and statisticians, who seem to be of a rather different opinion, supported by the international standards for the reliability of research; but I'm sure you're right.   

Perhaps you could tell us what type of helmet research is more reliable?  According to those international standards that is, not your opinion.  Please don't say case control studies; my sides hurt enough already.

We've discussed this previously Burt.

If you Google 'hierarchy of evidence' you'll find, to your horror, that case control studies are considered higher quality evidence than whole population studies for precisely the reasons I've explained in this thread.

I very much doubt that this knowledge will stop you repeating your claims. Even when you know they're not true. There's a word for that.

Rich_cb wrote:

burtthebike wrote:

You really must explain your opinion of whole population, long term research to epidemiologists and statisticians, who seem to be of a rather different opinion, supported by the international standards for the reliability of research; but I'm sure you're right.   

Perhaps you could tell us what type of helmet research is more reliable?  According to those international standards that is, not your opinion.  Please don't say case control studies; my sides hurt enough already.

We've discussed this previously Burt. If you Google 'hierarchy of evidence' you'll find, to your horror, that case control studies are considered higher quality evidence than whole population studies for precisely the reasons I've explained in this thread. I very much doubt that this knowledge will stop you repeating your claims. Even when you know they're not true. There's a word for that.

We all know that if you want to test the level of protection an individual helmet provides then testing individual cases where a helmet provided protection is the way to do it.  

Only an idiot would be presenting that argument in regards to the effectiveness of helmet "laws" whose very purpose is to reduce head injuries to populations and not individuals.

Proclaiming that helmet laws change the population level makeup of cycling and that is the reason that population level studies are unreliable is simply idiotic.  If you've decimated utility cycling that has significant negative social and health consequences which would far exceed the (limited) protective capabilities of helmets.  

It beggars belief that you're claiming that no evidence of a decrease in population level head injuries is not evidence that helmet laws aren't working.

jestriding wrote:

We all know that if you want to test the level of protection an individual helmet provides then testing individual cases where a helmet provided protection is the way to do it.  

Only an idiot would be presenting that argument in regards to the effectiveness of helmet "laws" whose very purpose is to reduce head injuries to populations and not individuals.

Proclaiming that helmet laws change the population level makeup of cycling and that is the reason that population level studies are unreliable is simply idiotic.  If you've decimated utility cycling that has significant negative social and health consequences which would far exceed the (limited) protective capabilities of helmets.  

It beggars belief that you're claiming that no evidence of a decrease in population level head injuries is not evidence that helmet laws aren't working.

Please stop putting words in my mouth.

I'm not defending helmet laws.

I've explained how population changes can distort whole population studies to such an extent that the results become highly misleading.

I was using examples to do that. Not endorsing helmet laws.

Rich_cb wrote:

We've discussed this previously Burt.

Yes and IIRC you were pretty rude last time too.

There's a word for that. In fact there are a few, none of which are flattering.

By all means disagree but if you want anyone to listen to your argument then don't be a ****.

Simon E wrote:

Yes and IIRC you were pretty rude last time too.

There's a word for that. In fact there are a few, none of which are flattering.

By all means disagree but if you want anyone to listen to your argument then don't be a ****.

Burt lies continually about this topic.

Why shouldn't he get called out?

Rich_cb wrote:

Simon E wrote:

Yes and IIRC you were pretty rude last time too.

 

There's a word for that. In fact there are a few, none of which are flattering.

By all means disagree but if you want anyone to listen to your argument then don't be a ****.

Burt lies continually about this topic. Why shouldn't he get called out?

you lie and are to be blunt live in a delusional fantasy world regarding how stuff works comparative to what happens in the real world. The very science/basic tests that tries to prove what you're saying does work, displays clearly it doesn't - or are you arguing also against what the helmet tests show us and that the equipment in these independant tests are faulty. And that you also deny the levels of and what constitutes brain trauma, concussions, TBIs etc. And also deny what experts in the field are saying, what data and evidence from multiple activities show us also (cricket, gridiron, skiing etc)

Just like Jake Olivier, you make up complete tosh to try to make your stance make sense, It's not worked in the past and like Olivier, you're failing repeated times over to convince people who have some semblance of logic, grasp of basic facts and living in reality.

Even the EU Road Safety commission which was promoting helmets and using the UK as a country that was being held up as being safer than NL and DK because of the higher helmet wearing rates (but were exposed by myself to the ECF and other orgs that they failed to recognise that using absolute numbers of deaths and not comparing rates was fraudulent/deliberately deceiving, and since then, the EU road safety commission have dropped all semblance of pushing cycle helmets as a road safety solution in their following reports and not mentioned their previous bullshit, maybe you could follow tack?? 

But no, carry on exposing yourself, carry on boxing yourself in sonshine and being a troll, there, I've called you out!

BehindTheBikesheds wrote:

you lie and are to be blunt live in a delusional fantasy world regarding how stuff works comparative to what happens in the real world. The very science/basic tests that tries to prove what you're saying does work, displays clearly it doesn't - or are you arguing also against what the helmet tests show us and that the equipment in these independant tests are faulty. And that you also deny the levels of and what constitutes brain trauma, concussions, TBIs etc. And also deny what experts in the field are saying, what data and evidence from multiple activities show us also (cricket, gridiron, skiing etc)

Just like Jake Olivier, you make up complete tosh to try to make your stance make sense, It's not worked in the past and like Olivier, you're failing repeated times over to convince people who have some semblance of logic, grasp of basic facts and living in reality.

Even the EU Road Safety commission which was promoting helmets and using the UK as a country that was being held up as being safer than NL and DK because of the higher helmet wearing rates (but were exposed by myself to the ECF and other orgs that they failed to recognise that using absolute numbers of deaths and not comparing rates was fraudulent/deliberately deceiving, and since then, the EU road safety commission have dropped all semblance of pushing cycle helmets as a road safety solution in their following reports and not mentioned their previous bullshit, maybe you could follow tack?? 

But no, carry on exposing yourself, carry on boxing yourself in sonshine and being a troll, there, I've called you out!

Firstly I'm glad you have finally acknowledged the difference between absolute and relative risk.

Maybe you can stop your regular rants about the absolute number of head injuries suffered by car passengers now?

Secondly, I'm glad that you have personally and directly influenced the EU Road Safety Commision.

What were you saying about delusions?

Rich_cb wrote:

We've discussed this previously Burt. If you Google 'hierarchy of evidence' you'll find, to your horror, that case control studies are considered higher quality evidence than whole population studies for precisely the reasons I've explained in this thread. I very much doubt that this knowledge will stop you repeating your claims. Even when you know they're not true. There's a word for that.

Whilst I generally don't respond to arrogant, insulting trolls, I'll make an exception in this case, but only because I'm in a playful mood; don't expect this all the time.  And I believe in educating the ignorant.

The briefest search turned up this "Case–control studies are therefore placed low in the hierarchy of evidence."

You might find this link of interest https://en.wikipedia.org/wiki/Hierarchy_of_evidence

burtthebike wrote:

Whilst I generally don't respond to arrogant, insulting trolls, I'll make an exception in this case, but only because I'm in a playful mood; don't expect this all the time.  And I believe in educating the ignorant.

The briefest search turned up this "Case–control studies are therefore placed low in the hierarchy of evidence."

You might find this link of interest https://en.wikipedia.org/wiki/Hierarchy_of_evidence

Now now Burt, don't go trying to weasel your way out of this.

You claimed that whole population studies were higher quality than case control studies.

I refuted that.

Where in your link does it support your claim exactly?

Rich_cb wrote:

Now now Burt, don't go trying to weasel your way out of this. You claimed that whole population studies were higher quality than case control studies. I refuted that. Where in your link does it support your claim exactly?

Weasel huh?

I saw a weasel walk into a pub. The barman asked it "What can I get you?"

"Pop" goes the weasel.

Rich_cb wrote:

Please don't listen to Burt. Whole population studies are very unreliable as there are so many other variables that cannot be excluded. This is especially true if there are big changes in the population you are studying. Mandatory helmet laws produce such changes thereby making whole population data worthless.

But logic suggests that 'social pressure' and propagandising would have an effect on a continuum with laws.  So what point are you trying to make?  In what ideal world can people all be pursuaded to wear helmets, while simultaneously having no effect on the population?

You seem to be arguing about some (platonic?) ideal world in which your case studies are applicable, entirely clear of all population effects.  But as that world doesn't exist I'm not sure what your point is.

FluffyKittenofTindalos wrote:

But logic suggests that 'social pressure' and propagandising would have an effect on a continuum with laws.  So what point are you trying to make?  In what ideal world can people all be pursuaded to wear helmets, while simultaneously having no effect on the population?

 

You seem to be arguing about some (platonic?) ideal world in which your case studies are applicable, entirely clear of all population effects.  But as that world doesn't exist I'm not sure what your point is.

The point I am making is that you cannot infer anything about the efficacy of bicycle helmets from whole population studies in countries with mandatory helmet laws.

Because the helmet wearing rate changes drastically at the exact same time that the cycling population changes drastically it is impossible to prove which variable has caused any observed effect.

The inability to control variables makes whole population studies unreliable. This is well known amongst researchers and published hierarchies of evidence reflect this.

When Burt states otherwise he is simply lying.

Rich_cb wrote:

Because the helmet wearing rate changes drastically at the exact same time that the cycling population changes drastically [/quote]

The latest paper from Australia denied that there were any cycling population changes...

So according to pro-cycling helmet law researchers in Australia there was no change in cycling population after the law was introduced and Australia now has more injuries and fatalities per billion kms than the UK.

jestriding wrote:

The latest paper from Australia denied that there were any cycling population changes...

 

So according to pro-cycling helmet law researchers in Australia there was no change in cycling population after the law was introduced and Australia now has more injuries and fatalities per billion kms than the UK.

That goes against all the other published data I've seen but please post a link, it would be interesting to read.

Rich_cb wrote:

jestriding wrote:

The latest paper from Australia denied that there were any cycling population changes...

 

So according to pro-cycling helmet law researchers in Australia there was no change in cycling population after the law was introduced and Australia now has more injuries and fatalities per billion kms than the UK.

That goes against all the other published data I've seen but please post a link, it would be interesting to read.

https://www.smh.com.au/national/report-reveals-how-many-lives-have-been-...

"Those who argue against helmet laws claim the laws have reduced interest in cycling, with many would-be cyclists hesitant to ride because they don't want to wear one".

"The paper's co-author, Professor Jake Olivier, who works at UNSW's School of Mathematics and Statistics and is deputy director of the Transport and Road Safety (TARS) Research Centre,  says there is no evidence to support this".

 He seems to have ignored that one of the few counts immediately after the law was introduced in 1992 found numbers dropped by 40% and cycling fatalities have increased 8% a year for the last decade.